MIDVALE, Utah (AP) — Three people were shot to death and one was critically wounded Tuesday at a known drug house in suburban Salt Lake City, causing temporary lockdowns at several area schools as police looked for two men who may have been involved.

Investigators said a person inside the house reported the shooting in Midvale at about 8 a.m.

Unified Police Department Lt. Justin Hoyal said a search warrant had been served at the residence in recent weeks for drug activity. "It was a known narcotics house," he said.

The house backs up to a sound barrier for Interstate 15 about 12 miles south of Salt Lake City.

Several elementary schools were locked down to keep children safe as dozens of officers began a search for David Fresques, 25, a "person of interest" who police believe was at the home at the time of the shooting.

Police found his car parked at a nearby Motel 6 and conducted a door-by-door search but didn't find him.

"He's a person of interest in a case where three people were murdered," Hoyal said. "Obviously, there's a dangerous individual out there."

Hoyal said a second person yet to be identified also might have information about the shooting. The school lockdowns were later lifted as police kept the schools under guard.

"We do not have a suspect in custody," Hoyal said.

The bodies of three people remained inside the house as police sought a search warrant to gather evidence. It wasn't certain when they would be removed.

The fourth shooting victim, a woman, was taken to a hospital in critical condition, Hoyal said.

Neighbors said they thought the house had been left vacant after police conducted the drug raid about two weeks ago.

"We heard a big boom at 4 o'clock in the morning," said Guy Foote, 50, who lives nearby. "They blew the door hinges off with flash grenades. The police were telling us to get back inside our houses."

He and other residents were shocked to learn a triple homicide had occurred in their tidy neighborhood of small houses.